“This module implements the Blowfish-based Unix crypt() password hashing algorithm, known as “bcrypt”. This hash uses a variant of Blowfish, known as “Eksblowfish”, modified to have particularly expensive key scheduling. Eksblowfish and bcrypt were devised by Niels Provos and David Mazieres for OpenBSD. The design is described in a paper at http://www.usenix.org/events/usenix99/provos.html.”